Rehabilitation of the SFE Pump Station Basis of Design Report - Updated

Revision: Updated Final

Rehabilitation of the SFE Pump Station Contract Number: 2000970

August 15, 2025

Rehabilitation of the SFE Pump Station Basis of Design Report - Updated

Client name: NORESCO for the Great Lakes Water Authority

Project name: Rehabilitation of the SFE Pump Station

Client reference: Contract Number: 2000970 Project no: C6A18000

Document no: 19660-10819660-108 Project manager: Allen Gelderloos. P.E.

Revision: Updated Final Prepared by: Jacobs

Date: August 15, 2025 File name: SFE_PS_BOD_Updated_Final-08-

Jacobs Consultants, Inc.

30800 Telegraph Road Suite 4900 Bingham Farms, MI 48025-4710 United States

T +1.248.633.1440 www.jacobs.com

Copyright © 2025.

All rights reserved. The concepts and information contained in this document are the property of the Jacobs group of companies. Use or copying of this document in whole or in part without the written permission of Jacobs constitutes an infringement of copyright. Jacobs, the Jacobs logo, and all other Jacobs trademarks are the property of Jacobs.

NOTICE: This document has been prepared exclusively for the use and benefit of Jacobs’ client. Jacobs accepts no liability or responsibility for any use or reliance upon this document by any third party.

230606111851_4c723a30 i

Executive Summary

Project Overview The Screened Final Effluent (SFE) Pump Station (PS) conveys water from the secondary effluent conduits to various treatment processes at the Detroit Water Resource Recovery Facility (WRRF). Uses of SFE water include incinerator scrubber water, biosolids dryer scrubber water, belt filter press wash water, elutriation water for gravity thickeners, and other various process and washdown uses. The existing SFE PS is nearly 50 years old and in poor condition, and its pumps are inefficient because they are oversized.

The WRRF also uses a large amount of potable water at a significant annual cost to Great Lakes Water Authority (GLWA). (After potable water from the water main along Jefferson Avenue goes through backflow preventers or break tanks on the WRRF site, the water is considered non-potable water, or secondary water [SW], which is the term used in this report). Providing treatment for SFE and replacing SW with treated SFE has been identified as both a cost-saving measure and a means to provide resiliency in case of a water main failure.

An Alternatives Evaluation Report was prepared and submitted to GLWA in April 2022. The findings and recommendations from the Alternatives Evaluation Report, along with a supplemental Engineering Design Abstract (EDA) submitted to GLWA on June 20, 2022, are summarized in Section 2.

This report provides the Basis of Design Report (BODR) for the recommended facilities and improvements related to a new SFE PS, SFE treatment system, and other ancillary pumping and backup disinfection systems.

The project is being delivered using a Progressive Design-Build delivery method under two phases. Jacobs is providing design services and NORESCO is the Prime Contractor.

Project Objectives This project is intended to accomplish the following objectives:

Replace the existing SFE PS with a new PS. The new PS will be “right-sized” to meet the current and anticipated future SFE demands and reduce energy costs.

Increase WRRF resiliency to a potable water main failure through the use of treated SFE (referred to as Low Pressure Secondary Water, or LPSW) as a primary source of SW water, with potable water as a readily available backup. Refer to Section 1.2 for further description of the improvements provided by this project.

Reduce WRRF operating costs by providing treatment to a portion of the SFE flow to make it suitable to replace SW uses throughout the WRRF.

Proposed SFE Pump Station Based on a review of existing and proposed SFE uses, the proposed SFE PS will have 60-mgd firm capacity (i.e., capacity with largest unit out of service). The proposed PS will be located north of the existing PS location, over the secondary effluent channels and use vertical turbine pumps, similar to the existing PS.

The proposed placement of pumps will position half of the pumps in the East Effluent Channel and half in the West Effluent Channel to allow one of these channels to be taken out of service, if necessary, and maintain current maximum day SFE supply. Table ES-1 provides the design criteria for the proposed SFE pumps.

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Table ES-1. Design Criteria for Proposed SFE Pumps and Ancillary Equipment

Parameter Value

SFE Pumps

SFE pump type, number of stages Vertical Turbine, 2 stages

Initial number of pumps (duty + standby) 6 (5 + 1)

Initial pump station firm capacity 60 mgd (5 pump in service)

Ultimate number of pumps (duty + standby + space for future) 8 ( 5 + 1 + 2)

Ultimate pump station firm capacity 84 mgd (7 pumps in service)

Capacity per pump 12.0 mgd at 187 feet TDH

TDH – minimum 163 feet

TDH – maximum 187 feet

Pump Drive Type Constant Speed

Motor size 500 hp

Motor Voltage 4,160V

Motor Speed 1,180 rpm hp = horsepower rpm = revolutions per minute

TDH = total dynamic head

V = volt(s)

VFD = variable-frequency drive

Complex II Incineration Quench Water Booster Pumps The new SFE Pump Station is designed to operate at a lower PS discharge pressure (about 65 to 70 pounds per square inch [psi]) compared to the existing PS discharge pressure (about 95 to 105 psi). It was found during the Alternatives Evaluation that providing a separate booster pumping system for the scrubber quench water in Complex II (C-II) Incineration would significantly reduce overall energy costs.

The proposed system includes two skids of two booster pumps each.

Increased Resiliency Provided by this Project One of the objectives of this project is to increase the WRRF resiliency to a water main failure by providing LPSW. Table ES-2 summarizes the primary and backup water supply included in this project to increase WRRF resiliency to a major potable water main failure.

Table ES-2. Summary of Increased Resiliency Provided by this Project

Water Use or Process Primary Water Supply Backup Water Supply

LPSW and IPSW LPSW Potable Water

HPSW Potable Water LPSW

SO2 Carrier Water DRO Potable Water

Chlorination Existing chlorine gas system using potable water as carrier water

Sodium hypochlorite from Hypo Building with SFE as carrier water

230606111851_4c723a30 iii

SFE Treatment The Alternatives Evaluation Report presented three alternatives for SFE filtration: cloth disk filters, granular media pressure filters, and granular media gravity filters. Cloth disk filters were selected in the EDA for implementation based on construction cost, simplicity, and footprint.

There will be two cloth disk filters, each with 14 disks, located in the Filter Room. Water will be pumped by the filter feed pumps (vertical turbine pumps) from the secondary effluent conduits to the filters.

Sodium hypochlorite (NaOCl) and sodium hydroxide (caustic, or NaOH) will be injected into filtered water upstream of a static mixer. Sodium hypochlorite is added to meet chlorine demand and limit nitrifier growth (and biofilm formation) in the distribution system. Caustic is added to match potable water alkalinity and limit sloughing of pipe scale in the distribution system. Downstream of the static mixer, water will drop through the floor into a filtered water storage tank (FWST). Sodium hypochlorite and caustic will each be stored in an indoor storage tank within a common chemical containment wall.

Connections of Treated SFE to Secondary Water System LPSW will be supplied using LPSW pumps from the FWST to the existing low, intermediate, and HPSW systems within the plant as either the primary or backup water supply. These connections will occur in the Machine Shop Basement. Modifications to these water supplies under this project are described as follows.

LPSW: LPSW will be pumped from the FWST into the LPSW system. The connection of LPSW to the LPSW system will be in the Machine Shop Basement. When the FWST reaches low level (indicating a sudden large increase in LPSW use in the plant), LPSW will be supplemented with potable water fed to the FWST. This will avoid large fluctuations in filtered water feed rates, which could negatively affect filtration performance.

IPSW: IPSW will be obtained from the LPSW system piping in the Machine Shop Basement and boosted to IPSW pressure by a new skid-mounted booster pump system in the basement.

HPSW: HPSW will remain on the potable water system and continue to be obtained from the existing break tanks in the Machine Shop Basement. New, right-sized HPSW pumps will be provided. As backup to potable water, LPSW will fill the break tank and be boosted using the same HPSW pumps.

Polymer makedown and boiler makeup are currently supplied by LPSW. These processes are considered too sensitive to use the proposed LPSW for supply. Therefore, the proposed HPSW system will feed these applications using pressure-reducing valves to achieve the proper feed pressure. This approach will ensure that potable water quality water will continue to be fed to these processes. LPSW will be provided as emergency backup.

Backup Potable Water Supply Potable water will serve as both a supplemental supply and a complete backup to the LPSW water supply.

An 16-inch potable water connection to the 42-inch Detroit Water and Sewerage (DWSD) water main on Jefferson Avenue will feed the Filter Room. Backflow prevention will be provided using reduced pressure zone (RPZ) backflow preventers. Figure ES-1A through Figure ES-1C provide schematics of the potable water connection to the LPSW system and three potential operating scenarios, described below:

1. Typical Operation: Filtered water feeds the FWST and the LPSW pumps convey the LPSW to the Machine Shop Basement for distribution to the secondary water system. No potable water is used in this operating scenario.

2. Supplemental Potable Water Supply: When the FWST reaches low level (indicating a sudden large increase in LPSW use in the plant), potable water will supplement the LPSW being fed to the FWST.

This will avoid large fluctuations in filtered water feed rates, which could negatively affect filtration performance.

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3. Potable Water as Secondary Water Backup: If a low water pressure (below an adjustable setpoint) occurs on the LPSW line feeding the Machine Shop Basement, the pressure control valve on the potable water bypass will automatically open and allow potable water to either provide the complete secondary water demand, or supplement the LPSW pumps.

230606111851_4c723a30 v

Sulfur Dioxide Carrier Water Carrier water used for conveying sulfur dioxide to the point of application in the Detroit River Outfall (DRO) is currently supplied by potable water. Under this project, plant effluent will be pumped from an existing DRO access shaft near the Dechlorination Facility to feed the existing carrier water booster pumps.. A new building with the carrier water pumps and strainers will be provided near the DRO access shaft to pump the water from the DRO. Potable water will be connected to the plant effluent water (referred to as DRO) with reduced pressure zone (RPZ) backflow preventers and a pressure sustaining valve to allow potable water backup to the carrier water supply. When the pumped DRO flow is less than needed (due to insufficient carrier water or a failure of the carrier water pumps), flow will be automatically supplemented with potable water.

Chlorination Carrier Water and Sodium Hypochlorite Backup Carrier water for conveying chlorine to the point of application at the Detroit WRRF site is currently supplied by potable water. The possibility of replacing this potable water with LPSW was evaluated and determined to be infeasible due to the risk of explosion when organic nitrogen or ammonia react with chlorine in the chlorine injectors. Potable water will continue to be used as carrier water for the chlorine injectors.

Alternatives for providing backup to the chlorination system were developed in the Alternatives Evaluation Report. The recommended alternative included in this project involves a backup hypochlorite feed system to feed hypochlorite from the Hypo Building to the existing chlorine solution diffuser feed locations in the secondary effluent conduits. The backup feed pumps will be located in the Hypo Building next to the existing hypochlorite feed pump skids. The pumps will pump hypochlorite into one of three chlorine solution feed lines, which will be isolated from the chlorine solution system during emergency operation and allow hypochlorite to be fed to the current diffuser feed point. SFE carrier water will be added to the feed line to provide mixing of the hypochlorite at the point of injection.

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Contents Executive Summary ............................................................................................................................................................ i

Project Overview ....................................................................................................................................................................... i Project Objectives ..................................................................................................................................................................... i Proposed SFE Pump Station ................................................................................................................................................ i Complex II Incineration Quench Water Booster Pumps ........................................................................................... ii Increased Resiliency Provided by this Project .............................................................................................................. ii SFE Treatment ......................................................................................................................................................................... iii Connections of Treated SFE to Secondary Water System ...................................................................................... iii Backup Potable Water Supply ........................................................................................................................................... iii Sulfur Dioxide Carrier Water ............................................................................................................................................... v Chlorination Carrier Water and Sodium Hypochlorite Backup .............................................................................. v

Acronyms and Abbreviations ......................................................................................................................................... ix

1. Introduction ........................................................................................................................................................ 1-1

1.1 Project Overview and Objectives ..................................................................................................................... 1-1

1.2 Increased Resiliency Provided by this Project ............................................................................................ 1-1

1.3 Locations of Facilities and Key Areas Described in Report ................................................................... 1-2

2. Summary of Alternatives Evaluation Report Findings and Recommendations ................................. 2-1

2.1 SFE Pump Station and Related Systems ...................................................................................................... 2-1

2.2 Complex II Incineration Quench Water Booster Pumps ......................................................................... 2-1

2.3 SFE Treatment ........................................................................................................................................................ 2-1

2.4 Connections of Treated SFE to Secondary Water System ..................................................................... 2-1

2.5 Sulfur Dioxide Carrier Water ............................................................................................................................. 2-2

2.6 Chlorination Carrier Water and Sodium Hypochlorite Backup ............................................................ 2-2

3. Design Development ........................................................................................................................................ 3-1

3.1 Introduction ............................................................................................................................................................. 3-1

3.2 Process ...................................................................................................................................................................... 3-1

3.3 Electrical ................................................................................................................................................................ 3-40

3.4 Instrumentation and Control ......................................................................................................................... 3-43

3.5 Site Civil.................................................................................................................................................................. 3-48

3.6 Structural ............................................................................................................................................................... 3-54

3.7 Architectural ......................................................................................................................................................... 3-59

3.8 Building Mechanical .......................................................................................................................................... 3-61

4. Permitting Plan .................................................................................................................................................. 4-1

4.1 Michigan Department of Environment, Great Lakes, and Energy ...................................................... 4-1

4.2 City of Detroit .......................................................................................................................................................... 4-1

4.3 Detroit Water and Sewerage Department ................................................................................................... 4-1

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Appendices Appendix A Referenced Design Drawings Appendix B Screened Final Effluent Hydraulic Model Review and Calibration Appendix C Detroit WRRF SFE Pump Station – Computational Fluid Dynamics Analysis Appendix D Detroit WRRF SFE PS Transients Surge Analysis Appendix E Geotechnical Investigation Report

Tables Table ES 1. Design Criteria for Proposed SFE Pumps and Ancillary Equipment ......................................................... ii Table ES 2. Summary of Increased Resiliency Provided by this Project ......................................................................... ii Table 1-1. Summary of Increased Resiliency Provided by this Project ...................................................................... 1-2 Table 3-1. Existing SFE Pump Information ........................................................................................................................... 3-2 Table 3-2. Flow Correction Factors .......................................................................................................................................... 3-6 Table 3-3. Current SFE Usage by Use and Location .......................................................................................................... 3-9 Table 3-4. SFE System Pressures with Constraint of 50 psi for Complex II Incineration Quench Water ... 3-11 Table 3-5. SFE System Pressures with Constraint of 40 psi for Complex II Incineration Booster Pumps . 3-11 Table 3-6. Current and Projected SFE Usage by Use and Location .......................................................................... 3-14 Table 3-7. Design Criteria for Proposed SFE Pumps and Ancillary Equipment ................................................... 3-15 Table 3-8. Basis for TDH for New SFE Pump Station with Boosted Quench Water ............................................ 3-16 Table 3-9. Flow Metrics for 12 mgd Pumps, Peak Flow, Option 2, Scenario 1 .................................................... 3-17 Table 3-10. Flow Metrics for 12 mgd Pumps, Peak Flow, Option 2, Scenario 6 ................................................. 3-20 Table 3-11. Weight of Various Equipment ......................................................................................................................... 3-21 Table 3-12. Filter Feed, LPSW Pump and Potable Water Fill Control Based on FWST WSE ........................... 3-24 Table 3-13. Filter Design Criteria ........................................................................................................................................... 3-25 Table 3-14.Filtered Water Storage Tank Design Criteria .............................................................................................. 3-27 Table 3-15. LPSW Pump Design Criteria ............................................................................................................................. 3-28 Table 3-16. Chemical Feed System Design Criteria ....................................................................................................... 3-29 Table 3-17. Chemical Feed System Pipe and Fitting Specifications ........................................................................ 3-30 Table 3-18. Secondary Containment Design Criteria .................................................................................................... 3-31 Table 3-19. IPSW Booster Pump Design Criteria ............................................................................................................. 3-32 Table 3-20. HPSW Pump Design Criteria ............................................................................................................................ 3-33 Table 3-21. SFE Scrubber Water Requirements for Each Incinerator ...................................................................... 3-34 Table 3-22. Quench Water Booster Pump Design Criteria .......................................................................................... 3-34 Table 3-23. Incinerator Strainer Flows and Capacity ..................................................................................................... 3-36 Table 3-24. SO2 Carrier Water and Booster Pumps Design Criteria ......................................................................... 3-37 Table 3-25. Backup Hypochlorite Feed System Design Criteria ................................................................................ 3-39 Table 3-26. Summary of the NEC Area Classification, Ventilation, and Fire Protection Requirements ..... 3-40 Table 3-27. Preferred Equipment Manufacturers ........................................................................................................... 3-43 Table 3-28. Yard Piping Materials ......................................................................................................................................... 3-53 Table 3-29. HVAC Space Design Criteria ............................................................................................................................ 3-62

Figures Figure 1-1. Location of Key Areas and Facilities Described in this Report ............................................................... 1-3 Figure 3-1. Plan View of the Existing SFE Pump Station ................................................................................................. 3-3 Figure 3-2. Schematic of the Existing SFE Pump System ............................................................................................... 3-4 Figure 3-3. SFE Yard Piping ........................................................................................................................................................ 3-5

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Figure 3-4. Historical SFE Daily Flows for 3-Year Period ................................................................................................ 3-6 Figure 3-5. Frequency Plot of SFE Flows Over 3-Year Period ....................................................................................... 3-7 Figure 3-6. Hourly SFE Flows for 1-Year Period ................................................................................................................. 3-8 Figure 3-7. SFE Pump Station Discharge Pressure for 3-Year Period ..................................................................... 3-12 Figure 3-8. Pump Curve Illustrating Increased Head at Lower Flows ...................................................................... 3-13 Figure 3-9. Streamlines Corresponding to Potential Moderate Vortices in the Pumps, 12 MGD Pumps, Peak

Flow, Option 2, Scenario 1 ........................................................................................................................................... 3-18 Figure 3-10. Streamlines Corresponding to Potential Weak Vortices (no vortices shown), 12 mgd Pumps, Peak Flow, Option 2, Scenario 6 with Fillets ......................................................................................................... 3-19 Figure 3-11. Critical Dimensions of the Fillets with 12 MGD pumps ...................................................................... 3-20 Figure 3-12. Overall Process Flow Diagram ...................................................................................................................... 3-23 Figure 3-13. Cloth Disk Filter Cut-Away View ................................................................................................................... 3-25 Figure 3-14. Proposed Location for Skid-Mounted Quench Water Booster Pumps .......................................... 3-35

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Acronyms and Abbreviations ˚F degree(s) Fahrenheit

AASHTO American Association of State Highway and Transportation Officials

AASI Aqua-Aerobic Systems Incorporated ach air changes per hour

ACI American Concrete Institute

ADWF average dry weather flow

AFD adjustable frequency drive

ANSI American National Standards Institute

ASCE American Society of Civil Engineers

ASD allowable stress design

ASHRAE American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc.

ASTM American Society for Testing and Materials

BDF biosolids drying facility

BOD basis of design cf cubic feet

CFD computational fluid dynamic

CGD Combustible Gas Detection

Cl2 chlorine

DC direct current

DRO Detroit River Outfall

EB electrical building

EDA Engineering Design Abstract

EGLE Michigan Department of Environment, Great Lakes, and Energy

FKE FK Engineering

FRP fiber-reinforced plastic

ft. (ft) feet ft2 square feet

FWST filtered water storage tank gal. gallon(s)

GLWA Great Lakes Water Authority gph gallons per hour

230606111851_4c723a30 x gpm gallon(s) per minute

HP high pressure hp horsepower

HPSW high-pressure secondary water

HSC hydraulic system centers

HVAC heating, ventilation, and air conditioning

I/O input/output

IBC International Building Code

ICEA Insulated Cable Engineers Association

IECC International Energy Conservation Code

IEEE Institute of Electrical and Electronic Engineers

IES Illuminating Engineers Society

IMC International Mechanical Code

IP intermediate pressure

IPC International Plumbing Code

IPSW intermediate-pressure secondary water

ISA Instrument Society of America lb/ft2 pound per square foot lb/ft3 pound per cubic foot

LPSW low-pressure secondary water

MBC Michigan Building Code

MCC motor control center mg/L milligram per liter mgd million gallons per day

NaOCl sodium hypochlorite

NaOH sodium hydroxide

NEC National Electric Code

NEMA National Electrical Manufacturers Association

NFPA National Fire Protection Association

Nos. number(s)

O&M operations and maintenance

OIT operator interface terminals

OSHA Occupational Safety and Health Act

230606111851_4c723a30 xi

P&ID piping and instrumentation diagram

PF peak flow

PLC programmable logic controller

POR preferred operating range

PS pumping station psi pounds per square inch psig pounds per square inch gauge rpm revolutions per minute

RRO Rouge River Outfall

SCADA supervisory control and data acquisition

SESC Soil Erosion and Sediment Control sf square feet

SFE screened final effluent

SMACNA Sheet Metal and Air Conditioning Contractor’s National Association

SO2 sulfur dioxide

SP submersible pump

SQL structured query language

SW secondary water

TDH total dynamic head

TEFC totally enclosed, fan cooled

TSS total suspended solids

UL Underwriters Laboratory

UPS uninterruptible power supply

UV ultraviolet

VFD variable-frequency drive

WRRF Water Resource Recovery Facility

WSE water surface elevation

230606111851_4c723a30 1-1

1. Introduction

1.1 Project Overview and Objectives

The Screened Final Effluent (SFE) Pump Station (PS) conveys water from the secondary effluent conduits to various treatment processes at the Detroit Water Resource Recovery Facility (WRRF). Uses of SFE water include incinerator scrubber water, biosolids dryer scrubber water, belt filter press wash water, elutriation water for gravity thickeners, and other various process and washdown uses. The existing SFE PS is nearly 50 years old and in poor condition, and its pumps are inefficient because they are oversized.

The WRRF also uses a large amount of potable water at a significant annual cost to Great Lakes Water Authority (GLWA). (After potable water from the water main along Jefferson Avenue goes through backflow preventers or break tanks on the WRRF site, the water is considered non-potable water, or secondary water [SW], which is the term used in this report). Providing treatment for SFE and replacing SW with treated SFE has been identified as both a cost-saving measure and a means to provide resiliency in case of a water main failure.

An Alternatives Evaluation Report was prepared and submitted to GLWA in April 2022. The findings and recommendations from the Alternatives Evaluation Report, along with a supplemental Engineering Design Abstract (EDA) submitted to GLWA on June 20, 2022, are summarized in Section 2.

This report provides the Basis of Design Report (BODR) for the recommended facilities and improvements related to a new SFE PS, SFE treatment system, and other ancillary pumping and backup disinfection systems.

This project is intended to accomplish the following objectives:

Replace the existing SFE PS with a new PS. The new PS will be “right-sized” to meet the current and anticipated future SFE demands and reduce energy costs.

Increase WRRF resiliency to a potable water main failure through the use of treated SFE (referred to as Low Pressure Secondary Water, or LPSW ) as a primary source of SW water, with potable water as a readily available backup. Refer to Section 1.2 for further description of the improvements provided by this project.

Reduce WRRF operating costs by providing treatment to a portion of the SFE flow to make it suitable to replace SW uses throughout the WRRF.

The project is being delivered using a Progressive Design-Build delivery method under two phases. Jacobs is providing design services and NORESCO is the Prime Contractor. Phase 1 will provide a 60% Design and allow for NORESCO to generate a Lump Sum.

1.2 Increased Resiliency Provided by this Project

As noted previously, one of the objectives of this project is to increase the WRRF resiliency to a water main failure by providing treated LPSW. Increased resiliency is provided by the following improvements:

1. For existing low-pressure secondary water (LPSW) and Intermediate pressure secondary water (IPSW), LPSW (treated SFE) will replace potable water as the primary source of water. The new LPSW will be produced through filtration and chemical addition (sodium hypochlorite to provide a monochloramine residual and sodium hydroxide to provide alkalinity) of the secondary effluent. Potable water will serve as the backup water supply to the LPSW and IPSW through a connection of a potable water line to the LPSW line with proper backflow prevention.

2. For high-pressure secondary water (HPSW), potable water will remain the primary source of water, based on the need for higher water quality for this supply. As a short-term emergency backup (i.e., two

230606111851_4c723a30 1-2 to three days), LPSW will be piped to feed a HPSW break tank to serve as a readily available backup water supply.

3. For sulfur dioxide carrier water at the Dechlorination Facility, screened secondary effluent (referred to as Detroit River Outfall [DRO]) will replace potable water as the primary source of carrier water. DRO will be pumped from the DRO access shaft near the Dechlorination Facility to a connection with backup potable water and then routed to the sulfur dioxide carrier water booster pumping system.

Potable water will serve as the backup water supply through a connection in the Maintenance Room, which will provide reduced pressure zone (RPZ) backflow prevention.

4. For chlorine carrier water at the Chlorination Facility, the possibility of replacing potable water with LPSW was evaluated and determined to be infeasible due to the risk of explosion when organic nitrogen or ammonia react with chlorine in the chlorine injectors. Potable water will continue to be used as carrier water for the injectors.

5. Alternatives for providing backup to the chlorination system were developed in the Alternatives Evaluation Report. The recommended alternative included in this project involves a backup hypochlorite feed system to feed hypochlorite from the Hypo Building to the existing chlorine solution diffuser feed locations in the secondary effluent conduits. The backup feed pumps will be located in the Hypo Building next to the existing hypochlorite feed pump skids. The pumps will pump hypochlorite into a feed line to one of the three chlorine solution lines, which will be isolated from the chlorine solution system and allow hypochlorite to be fed to the current diffuser feed point. SFE carrier water will be added to the feed line to provide mixing of the hypochlorite at the point of injection.

Table 1-1 summarizes the primary and backup water supply previously described and included in this project to increase WRRF resiliency to a major potable water main failure.

Table 1-1. Summary of Increased Resiliency Provided by this Project

Water Use or Process Primary Water Supply Backup Water Supply

LPSW and IPSW LPSW Potable Water

HPSW Potable Water LPSW

SO2 Carrier Water DRO Potable Water

Chlorination Existing chlorine gas system using potable water as carrier water

Sodium hypochlorite from Hypo Building with SFE as carrier water

1.3 Locations of Facilities and Key Areas Described in Report Figure 1-1 provides an aerial view of the location of key areas and facilities described in this report.

Appendix A provides additional details in site plan drawings referenced in this report.

230606111851_4c723a30 1-3

Figure 1-1. Location of Key Areas and Facilities Described in this Report

230606111851_4c723a30 2-1

2. Summary of Alternatives Evaluation Report Findings and Recommendations

This section summarizes the recommendations for the SFE PS and treatment systems from the Final Alternatives Evaluation Report, dated July 5, 2022. It also includes recommendations contained in the EDA, dated June 20, 2022.

2.1 SFE Pump Station and Related Systems

The Alternatives Evaluation Report recommended a new SFE PS at a location over the secondary effluent conduits, north of the existing SFE PS. The recommended firm capacity of the PS was 60 mgd. Various alternative pump combinations were evaluated, and an alternative with six variable speed pumps was the recommended alternative.

During 30% design review, GLWA requested space be provided for two additional, similarly sized SFE pumps, for a total space of eight pumps. Also, GLWA requested that the variable speed drives be replaced with constant speed pumps, based on historical issues with variable speed drives.

2.2 Complex II Incineration Quench Water Booster Pumps

The new SFE Pump Station is designed to operate at a lower PS discharge pressure (about 65 to 70 pounds per square inch [psi]) compared to the existing PS discharge pressure (about 95 to 105 psi). It was found during the Alternatives Evaluation that providing a separate booster pumping system for the scrubber quench water in Complex II (C-II) Incineration would significantly reduce overall energy costs.

The proposed system includes four skids of booster pumps, one skid for each pair of incinerators, and is described further in Section 3.2.4.

Based on GLWA preference, the system was changed to two skids of two pumps each distributing to all eight incinerators.

2.3 SFE Treatment

The Alternatives Evaluation Report presented three alternatives for SFE filtration: cloth disk filters, granular media pressure filters, and granular media gravity filters. Cloth disk filters were selected in the EDA for implementation based on construction cost, simplicity, and footprint.

There will be two cloth disk filters, each with 14 disks, located in a building. There will be a platform between the two filters, accessed by stairs.

Sodium hypochlorite (NaOCl) and sodium hydroxide (caustic, or NaOH) will be injected into filtered water upstream of a static mixer. Sodium hypochlorite is added to meet chlorine demand and limit nitrifiers growth (and biofilm formation) in the distribution system. Caustic is added to match potable water alkalinity and limit sloughing of pipe scale in the distribution system. Downstream of the static mixer, water will drop through the floor into a filtered water storage tank (FWST). It is impractical to pump sodium hypochlorite from the Hypo Building to the SFE treatment area. Therefore, sodium hypochlorite and caustic will each be stored in an indoor storage tank within a common chemical containment area.

Metering pumps will be near the containment wall with their wet ends inside the containment area.

2.4 Connections of Treated SFE to Secondary Water System

LPSW will be supplied to the existing low, intermediate, and HPSW systems within the plant as either the primary or backup water supply. These connections will occur in the Machine Shop Basement.

Modifications to these water supplies under this project are described as follows.

230606111851_4c723a30 2-2

LPSW: Treated SFE will be pumped from the FWST into the LPSW system. The connection to the LPSW system will be in the Machine Shop Basement. When the filtered water storage tank reaches low level (indicating a sudden large increase in LPSW use in the plant), treated SFE will be supplemented with potable water fed to the FWST. This will avoid large fluctuations in filtered water feed rates, which could negatively affect filtration performance.

IPSW: IPSW will be obtained from the LPSW system piping in the Machine Shop Basement and boosted to IPSW pressure by a new skid-mounted booster pump system in the basement.

HPSW: HPSW will remain on the potable water system and continue to be obtained from the existing break tanks in the Machine Shop Basement. New, right-sized HPSW pumps will be provided. As backup to potable water, LPSW will fill the break tank and be boosted using the same HPSW pumps.

Polymer makedown is currently supplied by LPSW. This process is considered too sensitive to use the proposed LPSW (treated SFE) for supply. Therefore, the proposed HPSW system will feed these applications using pressure-reducing valves to achieve the proper feed pressure. This approach will ensure that potable water quality water will continue to be fed to these processes.

During the Basis of Design phase for this project, boiler makeup was thought to be supplied by LPSW.

Further investigation during 60% design discovered it was connected to the potable water system.

Because of the potable water supply, it is not possible to connect the LPSW (treated SFE) to the potable water system. It was decided during 60% design to keep the boiler makeup water solely on the potable water system.

2.5 Sulfur Dioxide Carrier Water

Carrier water used for conveying sulfur dioxide to the point of application in the Detroit River Outfall (DRO) is currently supplied by potable water. Under this project, plant effluent will be pumped from an existing DRO access shaft near the Dechlorination Facility to feed the existing carrier water booster pumps.

A new building with the carrier water pumps and strainers will be provided near the DRO access shaft to pump the water from the DRO. Potable water will be connected to the plant effluent water (referred to as DRO) with reduced pressure zone (RPZ) backflow preventers and a pressure sustaining valve to allow potable water. When the pumped DRO flow is less than needed (due to insufficient carrier water or a failure of the carrier water pumps), flow will be automatically supplemented with potable water.

The proposed system is described further in Section 3.2.5.

2.6 Chlorination Carrier Water and Sodium Hypochlorite Backup Carrier water for conveying chlorine to the point of application at the Detroit WRRF site is currently supplied by potable water. The possibility of replacing this potable water with treated SFE was evaluated and determined to be infeasible due to the risk of explosion when organic nitrogen or ammonia react with chlorine in the chlorine injectors. Potable water will continue to be used as carrier water for the injectors.

Alternatives for providing backup to the chlorination system were developed in the Alternatives Evaluation Report. The recommended alternative included in this project involves a backup hypochlorite feed system to feed hypochlorite from the Hypo Building to the existing chlorine solution diffuser feed locations in the secondary effluent conduits. The backup feed pumps will be located in the Hypo Building next to the existing hypochlorite feed pump skids. The pumps will pump hypochlorite into a feed line to one of the three chlorine solution lines, which will be isolated from the chlorine solution system during emergency operation and allow hypochlorite to be fed to the current diffuser feed point. SFE carrier water will be added to the feed line to provide mixing of the hypochlorite at the point of injection.

The proposed system is described further in Section 3.2.6.

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3. Design Development

3.1 Introduction

This section describes the BOD for the recommended elements of this project, as described in Section 2.

The descriptions are provided by design discipline, as follows:

Process Electrical Instrumentation and Control Site Civil Structural Architectural Building Mechanical

3.2 Process

This section provides BOD information for the following process-related tasks included in this project:

SFE PS

SFE treatment including filter feed pumps, filters, treated SFE pumps, and chemical storage and feed systems

Connections and modifications to LPSW, IPSW, and HPSW in the Machine Shop Basement

C-II Incineration quench water booster system

SO2 carrier water system

Backup hypochlorite feed as backup to chlorine solution

Secondary effluent sampling system

3.2.1 SFE Pump Station

3.2.1.1 Background Information for Existing SFE Pump Station and System The existing SFE PS is located on top of the secondary effluent conduits north of the Administration Building. There are eight vertical turbine 2-stage pumps, with a total capacity of about 180 mgd.

Table 3-1 provides the existing pump information. The secondary effluent is screened through a strainer (one per pump) where suspended solids larger than 1/32 of an inch are removed. The strainers are backwashed to prevent clogging. Currently, the operations staff manually perform backwashing; however, an automatic backwash system had been previously installed and was operational. The backwash water is returned to the head of the treatment plant through the plant drains.

Figure 3-1 presents a plan view of the existing SFE PS, and Figure 3-2 provides a schematic view of the SFE pump and discharge piping.

230606111851_4c723a30 3-2

Table 3-1. Existing SFE Pump Information

Pump Design Information Pumps 1, 3, 4, 5, 7, and 8 Pumps 2 and 6

Manufacturer Peerless Peerless

Size/model 32HXS 26HXS

Type Vertical Turbine Vertical Turbine

Flow, gpm (mgd) 13,000 (25.2) 10,500 (15.2)

TDH (rated), feet 185 186

Motor, hp 1,000 600

Motor, voltage 4,160 4,160

Speed, rpm 885 1,180 hp = horsepower rpm = revolutions per minute TDH = total dynamic head

230606111851_4c723a30 3-3

Figure 3-1. Plan View of the Existing SFE Pump Station

Source: GLWA SFE Standard Operating Procedure Manual

SFE PUMP

STRAINER (TYP.)

BACKWASH

VALVE (TYP.)

DISCHARGE VALVE (TYP.)

CHECK VALVE

SF

E

PR

ES

SU

R

E M

AI

N

SF

PR

ES

SU

R

E M

AI

BA

C

K W

A

SH

H

EA

D

R

BACKWASH SUPPLY

VALVE (TYP.)

BO

O

ST

ER

P U

M P

R O

O M

EL

EC

TR

IC

AL

B U

IL

D

IN

G

TO

Y

AR

D

PI

TO

Y

AR

D

230606111851_4c723a30 3-4

Figure 3-2. Schematic of the Existing SFE Pump System

Source: GLWA SFE Standard Operating Procedure Manual

3.2.1.2 Existing SFE Distribution System

Figure 3-3 presents the SFE distribution system around the plant site. SFE flow is monitored by two transit time flow meters, with one meter on the 60-inch main and one meter on the 48-inch main. The flow to the Biosolids Drying Facility (BDF) is not measured through these meters; it is separately measured at the BDF.

The major uses of SFE are at the following locations; Section 3.2.1.5 provides the measured or calculated flows at each location:

Incineration Complex II Sludge Processing Complex A Sludge Processing Complex B Sludge Dewatering Complexes I and II

BDF

PS-1 - Rack and Grit Complex Hypo Building Primary Clarifiers

FLOW INDICATOR

MANUAL VALVE

PRESSURE GAUGE

M MOTOR ACTUATOR

BUTTERFLYL VALVE

PRESSURE SWITCH

DIFFERENTIAL PRESSURE SWITCH

PRESSURE REGULATOR

HAND STRAINER

SYMBOL LEGEND

3-5

Figure 3-3. SFE Yard Piping

3-6

3.2.1.3 Evaluation of Historical SFE Usage

Figure 3-4 shows the daily average SFE flow through the three flow meters, the 24-inch, 48-inch, and 60-inch. The average daily flow for the 3 years (from June 2018 to May 2021) varied from 15 to 38 mgd, with an average of 24 mgd. The flow data from Ovation were revised by applying the correction factors obtained from dye tests conducted by the GLWA Wastewater Analytics Task Force. Table 3-2 provides the correction factors for the three flow meters. Figure 3-5 provides a frequency plot of the 3 years of flow data. Figure 3-6 provides hourly data to illustrate the relatively limited fluctuations in SFE flow that occur throughout the day. Table 3-3 details the current SFE usage by use and location.

Table 3-2. Flow Correction Factors

Period 24 Inch Flow Meter 48 Inch Flow Meter 60 Inch Flow Meter

June 2018 to April 2020 1.0000[a] 0.9585 0.9958

May 2020 to October 2021 1.1560 0.9844 1.1560 [a] Correction factor of 1.0000 was determined to be from May 2019 to April 2020. The same correction factor is assumed for June 2018 to April 2019.

Figure 3-4. Historical SFE Daily Flows for 3-Year Period

3-7

Figure 3-5. Frequency Plot of SFE Flows Over 3-Year Period

3-8

Figure 3-6. Hourly SFE Flows for 1-Year Period

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Table 3-3. Current SFE Usage by Use and Location

SFE Use Type No. of Units In Service Total No. of Units Flow per Unit, gpm Typical SFE Usage, gpm Source of Flow Information

C-II Incineration Scrubber Water 4 8 2,120 8,480 Scrubber manufacturer P&ID; review of SCADA

C-II Incineration Strainer Backwash -- -- -- 400 5% of C-II Incineration Scrubber Water

Complex A Thickener Makeup Water 4 6 600 2,400 Site observation and O&M staff input

Complex B Thickener Makeup Water 4 6 600 2,400 Site observation and O&M staff input

BDF Scrubber Water 3 4 600 1,800 90 percentile of flow rate for each train from SCADA data

C-I BFP Washwater 0 10 100 0 From BFP manufacturer specs

C-I BFP Conveyor Washwater 0 1 50 0 Estimated usage

C-II BFP (Upper Level) Washwater 6 12 100 600 From BFP manufacturer specs

C-II (Dewater and Incin) Conveyor Washdown 4 6 100 400 Estimated usage

C-II BFP (Upper Level) Strainer Backwash -- -- -- 30 5% of C-II Dewatering Washwater

PS 1 Rack and Grit -- -- -- 60 Two hose bibs for typical usage; Grit Channel flushing for maximum usage

C-II Incineration Wet Ash Booster Pump 0 1 1,600 0 Wet ash has not been used in 10 years; Incinerator Ash Study recommended maintaining

Primary Tank Cleaning -- -- -- 0 Based on 3 hoses at 600 gpm each

SFE PS Strainer Backwash -- -- -- 840 5% of Current Use Flow

Subtotal of Current Uses, gpm

17,410

Subtotal of Current Uses, mgd 25.1

No. = number O&M = operations and maintenance P&ID = piping and instrumentation diagram SCADA = supervisory control and data acquisition

230606111851_4c723a30 3-10

3.2.1.4 Evaluation of SFE Distribution System Pressure Requirements

In collaboration with the ongoing WRRF Yard Piping Upgrades project, a hydraulic model of the SFE distribution system was updated, verified, and calibrated to existing conditions under this SFE PS project.

Appendix B provides a description of the hydraulic model investigation.

Jacobs and Applied Science, Inc. investigated minimum pressure requirements for SFE uses throughout the WRRF. The pressure requirement of 50 psi for the Complex II Incineration quench water (located on the fourth floor of the building) is the existing controlling pressure requirement.

Table 3-4 presents pressures at various locations throughout the plant and various SFE PS flow scenarios (that is, minimum, average, and anticipated design capacity). As shown, to meet the 50 psi quench water pressure requirement, the SFE header pressure at the existing SFE PS location must be about 90 psi.

The next highest-pressure requirement in the SFE distribution system is 40 psi at the inlet of the existing booster pumps on the first floor for each venturi scrubber in Complex II Incineration.